Visible-Light-Induced Tandem Radical Brominative Addition/Cyclization of Activated Alkynes with CBr 4 for the Synthesis of 3-Bromocoumarins.

A visible-light-induced tandem radical brominative addition/spiro-cyclization/1,2-ester migration of activated alkynes with CBr 4 is developed. This protocol features good functional group tolerance, operational simplicity, and mild reaction conditions without the use of catalysts and external additives, providing easy access to valuable 3-bromocoumarins in generally high yields.